Looks good but you might want to look at <r08> because we were going to do the same thing and from this thread (http://www.chiefdelphi.com/media/photos/32356) we have decided not to because it is not really legal. You need to have 6 in of bumper on the bumper peremeter on every exterior corner.

keen101

01-18-2009, 04:26 AM

I'm pretty sure they can do it that way, but would need to wrap bumpers around the corners. But, if I'm wrong please someone correct me!!

our front design is drafted with corners like that too, and if it will be illegal i need to know asap. From what I've read i think it can be covered within the rules, but I'm not entirely sure...

EricVicenti

01-18-2009, 04:31 AM

Very funny, when searching around for accumulator brush material on kickoff, we too discovered pneumatic tubing worked very well for this application. Our accumulator uses nearly the exact same system.

sanddrag

01-18-2009, 05:56 AM

Question: In a design such as this, is the bumper perimeter considered to go inward with the frame? If so, the roller would be outside the perimeter, and thus illegal.

GaryVoshol

01-18-2009, 06:48 AM

842 knows that their robot Carmen, as originally envisioned, does not meet the bumper rule: http://forums.usfirst.org/showthread.php?t=11170

Further discussion of their frame design can be found here: http://www.chiefdelphi.com/forums/showthread.php?t=71878 Note that this current pic has a portion of that frame removed; it looks like they're working on a fix to get legal bumpers.

Let's keep this thread on track discussing only the accumulator roller. It looks like a good design to me. The roller is inside the BUMPER PERIMETER and the soft pieces of tubing shouldn't harm the balls. My only question, have you done testing to see if that's enough little hooks to catch balls reliably?

Edit: I see from the video posting here http://www.chiefdelphi.com/forums/showthread.php?p=802925#post802925 it works pretty good. Nice!

MrForbes

01-18-2009, 09:40 AM

Another clever idea from 842, looks good!

rogeryoung

01-18-2009, 10:56 AM

I was concerned about pressure feed as well for drawing in the ball. I am anxious to get to school today and try this out. How about attaching the tubes with a short 10-32 stud threaded into the roller? Are those white rings pvc pipe? Are they "grooves" for round tubing?

Josh Goodman

01-18-2009, 11:00 AM

We prototyped with pneumatic tubing as well. It works very well and "sweeps" the balls in without touching the ground.

Akash Rastogi

01-18-2009, 12:00 PM

Hehe, cool to see one of the ideas we came up with on the first day was used :)

We might switch back to this design.

amariealbrecht

01-18-2009, 04:36 PM

wow this is a very cool and inventive idea...i like it!
have a good season,
Alicia Albrecht
Electrical subteam
The Robettes 2177

smurfgirl

01-18-2009, 05:52 PM

I like the design for the ball harvester. I saw the video of it, and it looks like it works really well. I think the little bits of tubing are a great idea!

falconmaster

01-18-2009, 08:49 PM

Question: In a design such as this, is the bumper perimeter considered to go inward with the frame? If so, the roller would be outside the perimeter, and thus illegal.

The bumper perimeter is defined as where a string wrapped around your robot would be. The string will not go into the opening and thus the bumpers would not be on the bumper perimeter. The bumpers in this case would count against the robot in its weight. We are still debating the legality of our bumper and we can make the argument for the configuration we currently have and we are prepared to modify if need be.

Mr_I

01-18-2009, 10:28 PM

Very similar to our design, although we don't (yet) have the diagonal supports. The notion of 6" bumpers is frightening, to the point of show-stopping (or at least "massive redesign"). 842, what are your thoughts?

falconmaster

01-18-2009, 10:40 PM

Well we feel that we will be allowed with our bumper design. W willadd bumpers to the diagonal sections with 6 inch sections. If we are not allowed we will swap them out with a straight six inch sections. Our argument though will be that the corners will be protected, no bumper section will be less than 6 inches and the weight of the part not on the bumper perimeter will be counted against the robot weight. Even if you had a straight section instead of diagonals the corners would not be protected on the inside. Oh well we will see

waialua359

01-18-2009, 11:16 PM

Its too bad that the bumpers are such a big issue.
The whole intent is to protect your own robot and other robots on the field, which should be the only things making contact with each other.
Instead, its turning into a wording or lack of wording issue.
I cant see how yours would be deemed illegal based on how you folks plan on putting them on.

IndySam

01-18-2009, 11:28 PM

Well we feel that we will be allowed with our bumper design. W willadd bumpers to the diagonal sections with 6 inch sections. If we are not allowed we will swap them out with a straight six inch sections. Our argument though will be that the corners will be protected, no bumper section will be less than 6 inches and the weight of the part not on the bumper perimeter will be counted against the robot weight. Even if you had a straight section instead of diagonals the corners would not be protected on the inside. Oh well we will see

Wow I think you are taking a big chance.

If I were your inspector I would rule that your angled bumpers do not qualify as BUMPERS.

Bob Steele

01-18-2009, 11:51 PM

I like your design but there is another rule that the bumpers must make first contact with the wall... I think your outside bumper corners should prevent your rollers from hitting the wall first... so that should be ok.

I would be careful though as another robot or trailer can hit the roller area... with the corner of their robot.. I can speak from experience in 2006 with a front roller that picked up the poof balls...

It was an issue then.. but of course ... in 2006 we didn't have mandated bumpers on the robot... just suggested...so we took many hits from unbumpered robots. We ended up having to use a titanium bar to protect our roller.

Good luck with your design... I hope it works great!!

Greg Needel

01-19-2009, 12:20 AM

Well we feel that we will be allowed with our bumper design. W willadd bumpers to the diagonal sections with 6 inch sections. If we are not allowed we will swap them out with a straight six inch sections. Our argument though will be that the corners will be protected, no bumper section will be less than 6 inches and the weight of the part not on the bumper perimeter will be counted against the robot weight. Even if you had a straight section instead of diagonals the corners would not be protected on the inside. Oh well we will see

i think you should look at this http://forums.usfirst.org/showthread.php?t=11170

waialua359

01-19-2009, 02:11 AM

wow. seems pretty black and white to me.

Wetzel

01-19-2009, 08:56 AM

We've built several iterations of intake and lift prototypes, and the tubes work well. What are you using to secure them to the roller?

Wetzel

Teched3

01-19-2009, 09:58 AM

Just another thought about your bumper design. Part of Team Update #3 is concerned with how far a trailer will enter your bumper perimeter. IMO, I don't think your design will pass inspection. As long as you have alternatives ready to modify, you won't be taking much of a chance. :)

keen101

01-19-2009, 10:45 AM

Well, were supposed to use a string to figure out our bumper perimeter. So, one interpretation would be that the angled bumpers would not be in the bumper perimeter, therefore you could still have them, but you'd have to consider them part of the robot and weigh them with the robot. But, that won't work either, because it clearly states that the trailer can only make contact with the bumpers, and if it made contact with the inside "bumpers", then that would technically be making contact with the robot. Even though it'd be a soft part of the robot.

So, i am concluding that it is illegal, and very risky to do it since we might have to change it later.

falconmaster

01-19-2009, 12:29 PM

We've built several iterations of intake and lift prototypes, and the tubes work well. What are you using to secure them to the roller?

Wetzel

plumbers goop or shoe goo.

XXShadowXX

01-19-2009, 12:36 PM

How fast does it propel the balls that pass under it?

JVN

01-19-2009, 12:49 PM

Well we feel that we will be allowed with our bumper design. W willadd bumpers to the diagonal sections with 6 inch sections. If we are not allowed we will swap them out with a straight six inch sections. Our argument though will be that the corners will be protected, no bumper section will be less than 6 inches and the weight of the part not on the bumper perimeter will be counted against the robot weight. Even if you had a straight section instead of diagonals the corners would not be protected on the inside. Oh well we will see

Send that inspector my way and we'll increase the size of our intake.

-John

falconmaster

01-19-2009, 12:53 PM

How fast does it propel the balls that pass under it?

It just takes an instant, may be 1/2 sec to 1 sec

Vikesrock

01-19-2009, 01:02 PM

Well we feel that we will be allowed with our bumper design. W willadd bumpers to the diagonal sections with 6 inch sections. If we are not allowed we will swap them out with a straight six inch sections. Our argument though will be that the corners will be protected, no bumper section will be less than 6 inches and the weight of the part not on the bumper perimeter will be counted against the robot weight. Even if you had a straight section instead of diagonals the corners would not be protected on the inside. Oh well we will see

Here's the problem with this. In order to protect the corner on the angled side the bumper will have to extend out past the corner itself placing it outside the bumper perimeter. With this being a bumper and not BUMPER it must fit within the volume constraints and would also redefine your bumper perimeter which would be problematic.

WhiteShadow1474

01-19-2009, 09:01 PM

how exactly did you get the pnumatic tubing to stay on there.

And; the bumper rules are so complex. I have no idea if this design is legal.

EricH

01-19-2009, 09:10 PM

how exactly did you get the pnumatic tubing to stay on there.

And; the bumper rules are so complex. I have no idea if this design is legal.

plumbers goop or shoe goo.

And as for legality, 3/4 sides of the robot are legal. The remaining side needs work.

Karthik

01-19-2009, 10:23 PM

And as for legality, 3/4 sides of the robot are legal. The remaining side needs work.

Well, according to Team 842 (see below), they believe all four sides are legal and don't need any remaining work. (Despite a fairly specific and clear Q&A entry.) I'm very interested in how this will play out. I'm sure many teams would like the extra space on their robot for their intake that 842 is planning to gain with their diagonal bumpers.

Well we feel that we will be allowed with our bumper design. W willadd bumpers to the diagonal sections with 6 inch sections. If we are not allowed we will swap them out with a straight six inch sections. Our argument though will be that the corners will be protected, no bumper section will be less than 6 inches and the weight of the part not on the bumper perimeter will be counted against the robot weight. Even if you had a straight section instead of diagonals the corners would not be protected on the inside. Oh well we will see

falconmaster

01-19-2009, 11:05 PM

Well, were supposed to use a string to figure out our bumper perimeter. So, one interpretation would be that the angled bumpers would not be in the bumper perimeter, therefore you could still have them, but you'd have to consider them part of the robot and weigh them with the robot. But, that won't work either, because it clearly states that the trailer can only make contact with the bumpers, and if it made contact with the inside "bumpers", then that would technically be making contact with the robot. Even though it'd be a soft part of the robot.

So, i am concluding that it is illegal, and very risky to do it since we might have to change it later.

Do the rules say the trailer contact part in rules that mention the trailer?

EricH

01-19-2009, 11:14 PM

Do the rules say the trailer contact part in rules that mention the trailer?
No, they don't. The trailer is, at least for the purposes of <G32>, also known as the robot-robot interaction rule, considered part of the robot. And, if there is bumper zone contact against unprotected robot, it is considered to be incidental bumper zone contact according to <G32-C> and therefore not a penalty. Note that if the contact is excessive or violates some other portion of the rule, a penalty may be assigned anyway.

Know the rules before you act on them/publish misinformation.

Andy L

01-19-2009, 11:21 PM

Am I the only one confused as to the dispute over the bumper legality? Didn't the GDC specifically say that the bumper configuration is illegal? And wouldn't you knowing this and still trying to dispute with your inspector be a little immoral?

ChuckDickerson

01-19-2009, 11:34 PM

Angled bumper debate aside, wouldn't a design of this type be illegal IF the roller (or parts of it like the pneumatic tubes in this example) touched a trailer? It is my understanding that the ONLY thing the robot is allowed to touch on the trailer is the BUMPER and then ONLY with the BUMPERS of the robot. If an intake roller mounted near the front edge of a robot intake opening touches the trailer (BUMPER or not) isn't it illegal? Due to the height of the BUMPERS (7") and diameter of the balls (~8.5") doesn't this severly limit the placement and design of intake rollers placed near the edge of a robot?

MrForbes

01-19-2009, 11:38 PM

Yes, it sound like the intake rollers would need to be more than 7" high, at the lowest point. Pokey grippy thingys might be a problem, if they're too long.

GaryVoshol

01-20-2009, 08:17 AM

We're using <R32> "ROBOT to ROBOT Interaction" to describe ROBOT to Trailer interaction, but that seems to also be the way the GDC is doing it.

B. Contact within the BUMPER ZONE is generally acceptable.

C. If a portion of the BUMPER PERIMETER polygon is unprotected by BUMPERS, any contact by another ROBOT within the unprotected region (including the vertical projection of the unprotected region) will be considered incidental contact and will not be penalized.

BUMPER ZONE Ė the volume contained between two virtual horizontal planes, one inch above the floor and seven inches above the floor.

The BUMPER ZONE extends both outside and inside your robot. The portion of your robot between 1 and 7 inches off the floor is included in your BUMPER ZONE.

Therefore one could argue that contact between 1 and 7 inches off the floor should be considered incidental.

ChuckDickerson

01-20-2009, 03:32 PM

I have re-read the rules and agree that <G32> defines what is and isn't allowed concerning ROBOT-to-ROBOT and ROBOT-to-TRAILER interactions. For reference this is the whole rule:

<G32> ROBOT to ROBOT Interaction - Strategies aimed solely at the destruction, damage, tipping over, or entanglement of ROBOTS or TRAILERS are not in the spirit of the FRC and are not allowed. In all cases involving ROBOT-to-ROBOT or ROBOT-to-TRAILER contact, the TEAM may receive a PENALTY and/or their ROBOT may be disqualified if the interaction is inappropriate or excessive. However, it is noted that Lunacy is a highly interactive game. Robust construction of ROBOTS will be very important in this high-speed competition. ROBOTS should be designed to withstand the contact that will occur during the MATCH. Appropriate contact is allowed under the following guidelines:

A. High speed accidental collisions may occur during the MATCH, and are an expected part of the game.

B. Contact within the BUMPER ZONE is generally acceptable.

C. If a portion of the BUMPER PERIMETER polygon is unprotected by BUMPERS, any contact by another ROBOT within the unprotected region (including the vertical projection of the unprotected region) will be considered incidental contact and will not be penalized.

D. Contact with a tilted or tipped ROBOT outside the BUMPER ZONE (particularly by the BUMPERS of the contacting ROBOT) will generally be considered incidental contact and will not be penalized.

E. Contact outside of the BUMPER ZONE is not acceptable, and will result in a PENALTY. The offending ROBOT may be disqualified from the MATCH if the offense is particularly egregious or if it results in substantial damage to another ROBOT.

F. A ROBOT may not attach to and/or climb onto a ROBOT or TRAILER. Doing so will be interpreted as an attempt to damage an opposing ROBOT, and will be penalized as such.

G. Use of any sloped or angled feature of the ROBOT as a wedge to overturn an opposing ROBOT or TRAILER is explicitly prohibited, and will be assigned a PENALTY.

1) Even though the rule is titled "ROBOT to ROBOT Interaction" by including the bolded "ROBOT-to-TRAILER" it is clear from the beginning that they are including robot to trailer interactions in this rule, however, robot to robot and robot to trailer interactions are somehow different since they specifically list them separately.

2) Section "E" clearly states that contact outside the BUMPER ZONE is not acceptable. There is no distinction made between ROBOTs and TRAILERs thus, since the rule is discussing the interactions of both, I have to assume that contact outside the BUMPER ZONE of the TRAILER is not allowed. This seems to be supported by this Q&A (http://forums.usfirst.org/showthread.php?t=11109) as well.

3) Section "C": "If a portion of the BUMPER PERIMETER polygon is unprotected by BUMPERS, any contact by another ROBOT" would imply ROBOT-to-ROBOT since TRAILERS have BUMPERS all the way around. There is no mention of TRAILER in section C. "another ROBOT" must mean that there is a one ROBOT to begin with, thus 2 ROBOTs, NOT a ROBOT and a TRAILER. Therefor section "C" does not define any "incidental contact" between ROBOTs and TRAILERs.

4) Section "D": Again only refers to ROBOTS. There is no mention of TRAILERS anywhere in "D". We better not run into a tipped over trailer and contact anything other than the (now semi vertical) bumpers.

By the combination of these parts of <G32> I have to come to the conclusion that the intent of this rule is to restrict ROBOT contact with the TRAILERs to BUMPER-to-BUMPER only. The rule is very careful to refer to ROBOTs and TRAILERs separately where desired. It is thus a false assumption that ROBOTs = TRAILERs as far as the "rules of engagement" go. FIRST cannot control or even conceive of how every team will construct their robots. It is perfectly logical to think that there may be two "U shaped"/"Open Front" robots on the field at the same time. It is also conceivable that the two "U shaped fronts" may come in contact with each other such that the legal bumpers of one robot protrude inside the legal width front "gap" of the other robot and make contact inside the robot with something other than a bumper. I conclude this to be the "incidental contact" referred to in section "C". Basically, if you build a robot with a gap within the BUMPER ZONE and another robot enters that area that is your problem, not FIRST's. However, we are all given detailed dimensional drawings of the trailer so we can't claim we didn't know what it looked like, how big it was, or how it was built. What I BELIEVE the GDC intent is to limit all contact with the trailer to the bumper only. I would even be willing to bet that at inspection there will be a legal TRAILER that will be pushed into and around your ROBOT and you better have designed it such that nothing but the BUMPERS of the trailer can touch your ROBOT inside and out. In other words, if you have an opening on the front of your robot such that the trailer can partially go inside your robot there is no such thing as "incidental contact" outside the bumper zone. The whole point of the drawings in Update #2 was to make sure we understood that the trailer bumper couldn't touch anything inside/under/etc. our robots, only the legal front minimum 6" bumpers. If you have an intake roller near the front of your robot with protrusions on it designed to grab the balls and pull them into your robot you better be careful that they can't touch the bumpers (or any other part) of the trailers.

Of course, this is just my interpretation of the rules. If others feel my logic is flawed in this interpretation please correct me.

EricH

01-20-2009, 04:22 PM

Of course, this is just my interpretation of the rules. If others feel my logic is flawed in this interpretation please correct me.
I'm going to offer a counter-argument here to some of your points, but not others. I've quoted the parts I refer to; I had the rules open while I answered.

I first look at each section of <G32> individually. Where appropriate, I comment on the above interpretations.

<G32>: General contact rule; all sub-rules are specific cases of this rule. I would argue that they specify robot-trailer to specifically include the trailer, so that teams are without excuse if they beat up the trailers, not to differentiate between robot-robot and robot-trailer contact.
<G32-A>: general expectation. It is NOT specific to either robot or trailer.
<G32-B>: general permissible contact volume. Again, not specific.
<G32-C>: Regarding unprotected areas of the bumper perimeter. Trailers have none, as they will be close enough to the towing robot to protect the tongue. Robots may. What's to stop an opponent from attempting to give a penalty by backing or swinging a trailer into an opening in the bumper perimeter, or worse, doing damage that way, if read as you interpret it? I would argue that the GDC wrote this for robot-robot interaction and overlooked it for robot-trailer interaction. They anticipated that the spirit of the rule would be understood.
<G32-D>: tilted/tipped robots. See my response on <G32-C>.
<G32-E>: outside of bumper zone contact. Not specific to either robot or trailer. Your interpretation is correct.
<G32-F>: climbing on robots/trailers. The first one to specifically instead of generally include the trailer.
<G32-G>: wedging robots/trailers. Also specifies both.

Only two sub-rules specify both robots and trailers, but the overall rule covers both. Three of the seven are general, mentioning neither. The other two rules are in spirit covering both, though not necessarily by letter. This has been known to happen before.

As for your conclusions, I separate them out piecemeal, to discuss them more easily.

1) "...intent of this rule is to restrict ROBOT contact with the TRAILERs to BUMPER-to-BUMPER only." The intent of the rule is to govern the entire contact between robots and either other robots or trailers, not to specify one particular type of contact between robot and trailer.

2) "It is thus a false assumption that ROBOTs = TRAILERs as far as the "rules of engagement" go." Where do you get this? As I said above, three rules are general, not counting the primary rule, and two more cover both the same.

3) "It is also conceivable that the two "U shaped fronts" may come in contact with each other such that the legal bumpers of one robot protrude inside the legal width front "gap" of the other robot and make contact inside the robot with something other than a bumper. I conclude this to be the "incidental contact" referred to in section "C"." This is part of the incidental contact. It is also conciveable that a team has no bumpers on one side of their robot, save at the corners, and a trailer accidentally, through no fault of either team, jams in there. I have a hard time thinking that that would be penalized. If it is, so be it, but in the past, it wouldn't be.

4) "What I BELIEVE the GDC intent is to limit all contact with the trailer to the bumper only." Remember that the trailer has bumpers all the way around. Which bumper, the one on the robot or the one on the trailer? If a trailer contacts a side of the robot that isn't protected, is that a penalty? I BELIEVE that the GDC's intent is to limit all contact to the bumper zone only.

5) "I would even be willing to bet that at inspection there will be a legal TRAILER that will be pushed into and around your ROBOT and you better have designed it such that nothing but the BUMPERS of the trailer can touch your ROBOT inside and out." I am equally willing to bet that there won't be one. Why? Extra weight to haul around, one more thing to be assembled at competition, and if anything other than bumpers can contact your robot, then I would suspect that you're awful close to an <R11> or <R08> violation anyway.

6) "In other words, if you have an opening on the front of your robot such that the trailer can partially go inside your robot there is no such thing as "incidental contact" outside the bumper zone." Where do you draw this from? The other rules, for example <G29>, don't say anything about this. You can push or react against any arena elements, and the trailer is an arena element.

7) "The whole point of the drawings in Update #2 was to make sure we understood that the trailer bumper couldn't touch anything inside/under/etc. our robots, only the legal front minimum 6" bumpers." The GDC has said repeatedly that those drawings are for illustrative purposes only. Attempts to draw anything more from them are frowned upon.

8) "If you have an intake roller near the front of your robot with protrusions on it designed to grab the balls and pull them into your robot you better be careful that they can't touch the bumpers (or any other part) of the trailers." This is more correct, as this could be construed as gabbing a trailer.

In short, I think that you're close, but a miss is as good as a mile. I think that <G32> covers both robot-robot and robot-trailer contact and treats them equally.

My apologies for the long post.

falconmaster

01-20-2009, 11:35 PM

OK, we have beaten to death. We will change our bot's front to have a six inch flat side on each side of our harvester's opening. It looks like it will not make too much of a difference , only ball's a ball width. We will just have to drive better! It was great watching all you debate the issue though, but if we stay with our design, we will loose the argument. We will bring our old angled side however in case we see the inspectors change their interpretation. Thanks all.

ChuckDickerson

01-21-2009, 12:48 AM

Eric, thanks for the great post in direct response to mine. Our two posts clearly show how two people can read the same words (rules) and come to two different conclusions. After reading your thoughtful and detailed response I can see how you arrived at your conclusions. However, not being able to read the minds of the GDC our team is opting to play it safe and is continuing to design and build our robot such that any contact between our robot and the trailer is bumper to bumper only (as long as the trailer is in itís normal playing configuration). Does this limit our design possibilities? Probably, but we would rather be safe than sorry. ;) We think we have a pretty good plan though. :D

EricH

01-21-2009, 01:05 AM

Eric, thanks for the great post in direct response to mine. Our two posts clearly show how two people can read the same words (rules) and come to two different conclusions. After reading your thoughtful and detailed response I can see how you arrived at your conclusions. However, not being able to read the minds of the GDC our team is opting to play it safe and is continuing to design and build our robot such that any contact between our robot and the trailer is bumper to bumper only (as long as the trailer is in itís normal playing configuration). Does this limit our design possibilities? Probably, but we would rather be safe than sorry. ;) We think we have a pretty good plan though. :D
Definitely play it cautious if you aren't sure. If nothing else, we showed how the contact rule needs work if they ever try trailers again.:D I also saw how you came to your conclusions. As it is written, both interpretations are valid without further clarification from above.

tacopaco789

01-22-2009, 02:19 AM

Just seeing that frame tells me that this belongs to the falcons. Light weight and sturdy. Same style from when we where allied with you in Phoenix the 2005 regional. Love it. lol :D

Kyle

Team 624
2007 Pit captain
2008 Build Captain
2008 Driver

ebarker

01-22-2009, 09:54 AM

To put Eric's comments into a nutshell -

a) a trailer is field equipment

b) thou shalt not damage field equipment

c) it has been so since the beginning of time.

I'd say that is the root cause of the GDC reasoning, rules and decisions on the matter.

JesseK

01-22-2009, 10:04 AM

Here's a tidbit we've found:

We've found that while on a slick surface, about half the time the orbit balls run away when they're hit wrong by the harvester fingers ... so having the roller edge @ 9" off the floor with the fingers extending down to 7.5" is our best solution. The harvester roller edge is 8" from the opposite conveyor side though, so the ball is under slight compression while in the conveyor.

Are you guys integrating tubing/belting in between the fingers for the conveyor? If so, have you solved the issue of the belting getting caught on the harvester fingers? That's our next thing to tackle.

falconmaster

01-22-2009, 01:12 PM

Here's a tidbit we've found:

We've found that while on a slick surface, about half the time the orbit balls run away when they're hit wrong by the harvester fingers ... so having the roller edge @ 9" off the floor with the fingers extending down to 7.5" is our best solution. The harvester roller edge is 8" from the opposite conveyor side though, so the ball is under slight compression while in the conveyor.

Are you guys integrating tubing/belting in between the fingers for the conveyor? If so, have you solved the issue of the belting getting caught on the harvester fingers? That's our next thing to tackle.

We came to some of the same conclusions. We are using 7 inch compression, hope thats not too much. We will show more detail of the harvester soon. We rae going to use polycord between the pneumatic tubing

Tristan Lall

01-25-2009, 03:33 PM

What I BELIEVE the GDC intent is to limit all contact with the trailer to the bumper only. I would even be willing to bet that at inspection there will be a legal TRAILER that will be pushed into and around your ROBOT and you better have designed it such that nothing but the BUMPERS of the trailer can touch your ROBOT inside and out. In other words, if you have an opening on the front of your robot such that the trailer can partially go inside your robot there is no such thing as "incidental contact" outside the bumper zone. The whole point of the drawings in Update #2 was to make sure we understood that the trailer bumper couldn't touch anything inside/under/etc. our robots, only the legal front minimum 6" bumpers. If you have an intake roller near the front of your robot with protrusions on it designed to grab the balls and pull them into your robot you better be careful that they can't touch the bumpers (or any other part) of the trailers.I'm still thinking this <G32> situation through, but I notice that the Q&A includes (http://forums.usfirst.org/showthread.php?t=11153) the following discussion:(1) are two pictured configurations in Update 2 "legal"? They seem to meet all parts of <R08> and thus we are assuming they are legal. Correct assumption?

(2) Is it acceptable for the robot to extend over the bumper zone of the TRAILER (not of the robot), that is the "opponent's trailer", as shown? is this "incidental contact"?

(3) If it IS ok to extend, any limits on reaching/touching the trailer posts?We believe that the two example illustrations in Team Update #2 are correct and satisfy the conditions defined in Rule <R08> as intended.

As shown in the illustrations, it is physically possible for a legal ROBOT configuration to partially enclose a TRAILER, including extending over the BUMPERS of the TRAILER. There are no rules that would prevent this, provided the TRAILER (including the BUMPERS, base, and vertical pipes) is not grasped, grappled, or attached to in a manner that would cause a violation of Rule <G29>).And <G29> states, in part, that "ROBOTS may push or react against any elements of the ARENA, provided there is no damage or disruption of the ARENA elements."

The way I interpret this, you can definitely touch the bars on other robots' trailers, without penalty, as long as you don't grasp/grapple/attach to, damage, climb or wedge the trailers.

By the way, here (http://forums.usfirst.org/showthread.php?t=11109)'s a question on a related topic, in which the GDC seems to ignore the question of touching a trailer's posts (concentrating on the part of the question dealing with spreading them). Although their non-answer is in no way definitive, it might be an indication that they don't consider mere contact a problem. (But they should really avoid non-answers.)